build.gradle.kts & multi-module-project: how to add other project so that transitive dependencies are available too

Question

Having the following multi-module-setup:

multi
├── projA
│   └── build.gradle.kts
├── projB
│   └── build.gradle.kts
├── build.gradle.kts
└── settings.gradle.kts

with the following content (abbreviated):

• settings.gradle.kts

  rootProject.name = "multi"
  include("projA", "projB")
  

• projA\build.gradle.kts

  dependencies {
      implementation("important-library:1.0")
  }
  

• projB\build.gradle.kts

  dependencies {
      implementation(project(":projA"))
  }
  

Why don't I have access to that importantlibrary:1.0 from projB?

What works: if I have a class within projA that uses the library, it works perfectly even if that class is called from a class within projB (so indirect access works). Directly accessing any class from importantlibrary:1.0 within projB doesn't work (unresolved reference).

What am I missing here? Or what needs to be set up so that it works?

Gradle version: 5.6.1

Answer 1

I think a good way to achieve what you want would be to use api instead of implementation. implementation is meant to only keep the dependency inside the module, while api is meant to export them along with the module. The dependencies for projA would then become:

dependencies {
    api("important-library:1.0")
}

This is the link to the official documentation: https://docs.gradle.org/current/userguide/java_library_plugin.html#sec:java_library_separation